Powder-actuated tool

ABSTRACT

A powder-actuated fastening tool of the piston type having a barrel assembly constructed to eliminate the build-up of undesirable residue in the tool. The barrel assembly is provided with at least one axially extending groove in its interior wall which is in communication with the atmosphere to vent the exhaust gas.

Unlted States Patent 1191 1111 3,910,477

Kavan Oct. 7, 1975 [5 POWDER-ACTUATED TOOL 3,494,125 2/1970 Robinson 227/10 x 3,514,025 5/1970 Hsu et a1 227/10 [75] Invent Kavan Toronto Canada 3,652,003 3/1972 Leonardo et a1. 227/10 [73] Assignee: Olin Corporation, New Haven,

Conn, Primary ExaminerGranville Y. Custer, Jr. Attorney, Agent, or FirmDona1d R. Motsko; H. [22] Flled May 1974 Samuel Kieser; William W. Jones [21] App]. No.: 467,338

[57] ABSTRACT 52 US. Cl 227/10;327/10; 327/1 A Powder-actuated fastening tool of the Piston yp [51] Int. Cl. l 1. B25c 1/14 having a barrel assembly constructed to eliminate the [58] Field of Search 227/8, 10, 11 P of undesirable residue in the tool- The barrel assembly is provided with at least one axially extend- [56] References Cited ing groove in its interior wall which is incommunica- UNITED STATES PATENTS tion with the atmosphere to vent the exhaust gas.

3,105,238 10/1963 Hilti 227/10 5 Claims, 3 Drawing Figures 1 64 2 3 50 z 1 58 101;: loanw 48 62 4 ,8 Z4 6 m 113 T f ZL. Z/ 1 5 2d 4 oz 4 J1 w 74 L 74 //z 5 04 4 38 U.S. Patent Oct. 7,1975

POWDER-ACTUATED TOOL BACKGROUND OF INVENTION This invention relates generally to the field of powder-actuated tools for driving fasteners or the like into masonry, concrete, wood, steel, or the like and more particularly, to an improved barrel assembly for such tools.

One type of powder-actuated tool for driving fasteners, studs, or the like includes a fastener driving member. The energy from the propellant-charge actuates the fastener driving member which in turn drives the fastener or stud into the work material. In tools of this type, there is sometimes a problem of residue being built up in the tool after many firings, rendering the tool partially or totally inoperable and requiring frequent cleaning;

This is especially a problem in tools which include a housing having a tubular forward portion in which a barrel assembly is mounted for axial reciprocal motion,

between a breech open position and a breech closed position. A fastener driving member is mounted inthe barrel assembly and is driven by the force of the gas generated by the ignition of the propellant charge from its driving position adjacent the propellant-charge receiving chamber at the breech end of the barrel to its driven position whereby a fastener positioned at the muzzle end of the barrel is driven into the work piece. The barrel assembly of tools of this type is provided with an axially extending groove in its side wall through which a pawl member mounted on the housing extends. The pawl member serves to return the pistonmember from its driven to its driving position when the barrel assembly is moved from its breech closed to its breech open position in a manner well known in the art.

SUMMARY OF INVENTION One object of the present invention is the provision of a powder-actuated tool of the type utilizing a fastener driving member wherein the build-up of undesirable residue is reduced.

A more specific object of the present invention is the provision of a powder-actuated tool having a barrel assembly constructed to reduce the build-up of undesirable residue.

These and other objects of the invention may be realized according to the preferred embodiment of the invention by providing at least one groove in the interior of the barrel assembly which extends axially forward from a point forward of the powder charge receiving chamber. The groove is in communication with the atmosphere whereby the gas and entrained residue is vented to the atmosphere.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a transverse sectional view of a tool embodying the present invention;

FIG. 2 is a transverse sectional view taken along the lines of 22 of FIG. 1; and

FIG. 3 is a transverse sectional view taken along the lines of 33 of FIG. 1.

DETAILED DESCRIPTION Referring specifically to the drawing, FIG. I shows a specific type of powder-actuated tool embodying the present invention in a specific formxThetool, in general, comprises a housing 2 includinga tubular forward portion 4 and a rearward portion 6. The tubular forward portion 4 includes an ejection port 8 which provides. access for loading and unloading a propellant charge, which may be in a metallic cartridge case or in 5 the form of a caseless charge. The rearward portion 6 of the housing 2 houses the firing mechanism 10 and also includes a pistol grip l2 anda trigger guard 14.

The firing mechanism 10 includes a breech face 16 having a frusto-conical opening 18 therein. A firing pin 20 is mounted behind the breech face 16 for axial movement in the housing 2 and includes a frustoconical nose portion 22, a body portion 24 and a rearwardly extending rodportion 26. The firing pin 20 is urged forwardly by a suitable spring member 28. A detent member 30 extends radially downwardly from the body protion 24 of the firing pin 20. The detent member 30 is spring biases outwardly by a suitable spring means 32.

A cocking rod 34 is mounted for reciprocation in the rearward portion 6 of the housing 2 and includes a forward portion 36 extending through the breech face 16 and into the tubular forward portion 4 of the housing 2. The cocking rod 34 may be spring biased forwardly by a suitable spring member 38. The cocking rod 34 may also include an elongated opening 40 through which the detent member 30 on the firing pin 20 may extend.

A trigger member 42 having a sear portion 44 may be pivotally mounted above the trigger guard 14 by a pivot pin 46. The trigger is resiliently urged away from the firing position by a spring member 48.

A barrel assembly 50 is reciprocally mounted within the forward tubular portion 4 of the housing 2 and extends from the muzzle end thereof. The barrel assembly 50 includes a barrel member 52 having a bore 54 therein, a muzzle bushing 56 threadedly secured within a threaded counterbore 58 at the forward or muzzle end of the barrel member 52, and a shroud member 59.

The barrel member. 52 includes a main barrel body 60 having a propellant charge receiving chamber 62 at its breech end for the reception of a propellant charge 64 which in the form shown in FIG. 1 comprises a metallic cartridge. The muzzle end 66 of the barrel member 52 into which the counterbore 58 extends is enlarged. A plurality of slots 68, 70, 72, and 74, are equally spaced about the side 'wall of the main barrel member body 60. There are four such slots in the preferred embodiment. A steel sleeve member 76 is press fitted onto the main barrel member body 60 and extends from a point adjacent the breech end thereof to the enlarged muzzle end 66. The sleeve member 76 covers the slots 68, 70', and 72 in the main barrel member body 60 and has a slot 78 therein which is coextensive with the bottom slot 74 in the main barrel member 60 to provide an opening for the pawl member 80. As the sleeve member 76 covers the slots 68, 70, and 72 in the main barrel member body 60, such slots actually form grooves in the barrel member 52 which do not extend through the barrel member 52.

The forward end of slots 68, 70, 72, and 74 terminate at a point rearward of the enlarged forward portion 66 of the barrel member 52. Arcuate grooves 80, 82, 84, and 86 are machined in the interior surface of the barrel member 52 and extend from the bottom of the counter bore 58 to the end of each of the slots 68, 70, 72, and 74. The grooves 80, 82, 84, and 86 arcuate in cross-section with a diameter greater than the width of the slots 68, 70, 72, and 74, but do not extend through mounted for reciprocal movement between a driving.

position and a driven position within the barrel assernbly 50. The piston member 96 includes a generally'cylindrical enlarged head portion 98 and a reduced elongated forward cylindrical shank portion 100. A piston ring 102 may be mounted within a suitable groove 104 which extends about the circumference of the head portion 98 of the piston member 96.

The muzzle bushing 56, which is threadedly secured to'the forward end of the barrel member 52, includes a bore 106 of lesser diameter than the diameter of the bore 54, of barrel member 52. The muzzle bushing 56 is provided with a counterbore 108 in its rearward surface. A suitable buffer member 110 is mounted in the counterbore 108 to absorb the energy of the piston member 96 in the event the piston member 96 is overdriven. In the preferred embodiment, the buffer member 110 comprises a hollow cylindrical member fabricated from any suitable material such as polyurethane, nylon, or other suitable elastomeric surface. The interior diameter of the buffer member 110 must be at least as great as the diameter of the bore 106 of the muzzle bushing 56, which in turn is of such a size as to slidably receive the shank portion 1000f the piston member 96. The buffer member 110 extends rearwardly in the tool out of the counterbore 108, into the bore 54 of the barrel member 52 for a short distance.

The shroud member 59 surrounds the muzzle end 66 of the barrel member 52 and includes an internal flange 11 l which is positioned between the forward end of the barrel member 52 and a shoulder 113 on the muzzle bushing 56. The shoulder 113 is spaced axially forwardly from the end of the barrel member 52 so that the shroud member 59 has some axial play. The enlarged muzzle end 66 of the barrel member 52 includes axially extending planar surfaces which intersect each of the ports 88, 90, 92, and 94 and have a width slightly greater than the diameter of the ports.

The pawl member 80 is threadedly attached to the forward end of the housing 2 and includes a stem portion 112 which extends through the slot 78 in the sleeve.

member 76 and the slot 74 in the main barrel body 60 into the interior of the barrel member, 52. The stem portion 1 12, in addition to serving as a barrel guide and stop means for limiting forward movement of the barrel assembly 50, also serves to return the piston member.

96 to its firing position by means of engagement by thestem portion 112 with the forward surface of the'head portion 98 of the piston member 96 as the barrel assembly 50 is moved into its forward position.

As is shown in FIG 1, the slots 68, '70, 72, and 74 extend axially forward from a point forward of the propellant charge receiving chamber 62 to a point slightly rearward of the enlarged forward portion 66 of the barrel member 52. The grooves formed in the barrel member 52 by the slots 68, 70, and 72 and grooves 80, 82,

and 84 extend from a point forward of the rearward 7 face of the enlarged head portion 98 of the piston member 96 when the piston member 96 is in its driving position to a point forward of the forward face of the enlarged head portion 980f the piston member 96 when the pistonmember is in its normal driven position. The

ports 88, 90, 92',and 94 are so positioned that when the barrel assembly 50 is moved into thetiring position, the ports are positionedaxially forward of the forward end of the housing 2.

In operation after a fastener is positioned in the bore 106 of the muzzle bushing 56 and a suitable propellant charge is positioned within the propellant charge receiving chamber62, the tool may be positioned against a suitable work surfacev To fire the tool, the operator must push down on the housing 2 to move the housing 30 of the firing pin20 is in operable alignment with the I sear portion 44 of the trigger member so that by pulling the trigger member 42 the sear portion 44 will release the detent 30 from the cocking rod 34 and the firing pin will fly forward under the action of its spring member 28 until the nose portion 22 thereof projects through the frusto-conicalopening 18 in the breech face of the propellant charge.

The gas generated by the actuation of the propellant charge will drive the piston .member 96 forwardly toward the muzzle end of the tool and drive the fastener into the work surface. As the rearward face ofthe head portion 98 of the piston member 96 passes the rearward end of the grooves in the barrel member 52 formed by the slots 68, 70, and 72 in the main barrel body 60, the gas will flow along such grooves, along the arcuate grooves 80, 82, and 84, and out through the ports 88, 90, and 92m the atmosphere. Due to the fact that the pawl member 8O extends into the slot 74, the flow of gas along the slot 74 and groove 86 will be somewhat restricted although it is possible that some gas will escape around the pawl member and flow along groove .86 and out through vent 94 to the atmosphere. The gas will carry along with it agood portion of the residue generated by the burning of the propellant charge. This results in a reduction of the amount of residue built up on the tool and permits a'greater. number of firings before the tool needs cleaning or becomes inoperable. The above described arrangement provides means for permitting the gas to escape to the atmosphere while maintaining proper guidance of the whether a separate muzzle bushing iseven used, it is 7 possible that the grooves can extend to the muzzle end of the tool at which point they communicate with the atmosphere. It is also'possible in theevent that the barrel assembly is substantially enclosed in a housing, that the vents providing communication between the grooves and the atmosphere could extend through the housing.

many changes and variations of the specific embodiment disclosed may be made without departing from the inventive concept. It is intended that the foregoing description of the preferred embodiment be considered as exemplary only and that thescope of this invention be ascertained from the following claims.

What is claimed is: l. A powder-actuated fastening tool including a housing having a forward tubular portion, a barrel assembly having a bore therein mounted for reciprocal movement between a breech open position and a breech closed position, a piston member in said bore moveable between a driving position and a driven position, a propellant charge receiving chamber in the breech end of the barrel assembly, a slot through the wall of the barrel assembly extending from a rearward point forward of said propellant charge receiving chamber to a point spaced axially rearwardly of the forward end of said housing when said barrel assembly is in its breech closed position, a pawl member mounted on said housing and having a portion extending through said slot into the bore in said barrel assembly, a groove in the interior wall of said barrel assembly extending from the forward end of said slot to a forward point which is axially forward of the forward end of said housing when said barrel assembly is in its breech closed position, at least one groove in the internal wall of the bore of said barrel assembly extending from a point forward of said propellant charge receiving chamber to a point axially forward of the forward end of said housing when said barrel assembly is in its breech closed position, and port means in said barrel assembly providing communication between all of said grooves and the atmosphere at a point forward of the forward end of said housing when said barrel assembly is in its breech closed position.

2. The powderactuated fastening tool of claim 1 further including a shroud member surrounding said barrel assembly at least in the region of the opening of said port means to the atmosphere.

3. A powder-actuated fastening tool including a housing having a forward tubular portion, a barrel assembly having a bore therein mounted for axial reciprocal movement in said forward tubular portion between a breech open position and a breech closed position. a piston member mounted in said bore moveable between a driving position and a driven position, said barrel assembly including a barrel member having an enlarged muzzle end, a muzzle bushing received in said muzzle end and extending forwardly therefrom, a propellant receiving chamber positioned at the breech end of said barrel member, said barrel member including a main barrel body having a plurality of slots extending from .a point axially forward of said propellant charge receiving chamber to a point rearward of said enlarged portion, a tubular sleeve surrounding said main barrel body and covering said slots, an arcuate groove in the internal wall of said main barrel body extending from theforward end of each of said slots to a point forward of the forward end of said housing when said barrel assembly is in its breech closed position, and port means located in the enlarged portion of said barrel member providing communication between said grooves and the atmosphere, said port means opening to the atmosphere at a point forward of the forward end of said housing when said barrel assembly is in its breech closed position.

4. The powder-actuated tool of claim 3 further including a shroud member covering said enlarged end of said barrel member, said shroud having a forward inturned flange, said muzzle bushing having stop means thereon for limiting forward movement of said shroud relative to said barrel assembly spaced from the forward end of said barrel member, said flange extending into the space between said stop means and the forward end of said barrel member, the outer surface of said enlarged portion of said barrel member having reduced planar portions intersecting said port means.

5. The powder-actuated tool of claim 3, said main barrel body having a further slot therein extending from a rearward point forward of said propellant charge receiving chamber to a forward point spaced rearwardly of the forward end of said housing when said barrel assembly is in its breech closed position, said tubular sleeve having a slot therein coextensive with said further slot, a pawl member mounted on said housing and having a portion extending through said slot in said sleeve and said further slot into the bore in said barrel assembly, a groove in the interior wall of said main barrel body extending from the forward end of said further slot to a forward point spaced axially forward of the forward end of said housing when said barrel assembly is in its breech closed position, and port means in said main barrel body providing communication between the forward end of the groove extending from said further slot and the atmosphere when the barrel assembly is in its breech closed position. 

1. A powder-actuated fastening tool including a housing having a forward tubular portion, a barrel assembly having a bore therein mounted for reciprocal movement between a breech open position and a breech closed position, a piston member in said bore moveable between a driving position and a driven position, a propellant charge receiving chamber in the breech end of the barrel assembly, a slot through the wall of the barrel assembly extending from a rearward point forward of said propellant charge receiving chamber to a point spaced axially rearwardly of the forward end of said housing when said barrel assembly is in its breech closed position, a pawl member mounted on said housing and having a portion extending through said slot into the bore in said barrel assembly, a groove in the interior wall of said barrel assembly extending from the forward end of said slot to a forward point which is axially forward of the forward end of said housing when said barrel assembly is in its breech closed position, at least one groove in the internal wall of the bore of said barrel assembly extending from a point forward of said propellant charge receiving chamber to a point axially forward of the forward end of said housing when said barrel assembly is in its breech closed position, and port means in said barrel assembly providing communication between all of said grooves and the atmosphere at a point forward of the forward end of said housing when said barrel assembly is in its breech closed position.
 2. The powder-actuated fastening tool of claim 1 further including A shroud member surrounding said barrel assembly at least in the region of the opening of said port means to the atmosphere.
 3. A powder-actuated fastening tool including a housing having a forward tubular portion, a barrel assembly having a bore therein mounted for axial reciprocal movement in said forward tubular portion between a breech open position and a breech closed position, a piston member mounted in said bore moveable between a driving position and a driven position, said barrel assembly including a barrel member having an enlarged muzzle end, a muzzle bushing received in said muzzle end and extending forwardly therefrom, a propellant receiving chamber positioned at the breech end of said barrel member, said barrel member including a main barrel body having a plurality of slots extending from a point axially forward of said propellant charge receiving chamber to a point rearward of said enlarged portion, a tubular sleeve surrounding said main barrel body and covering said slots, an arcuate groove in the internal wall of said main barrel body extending from the forward end of each of said slots to a point forward of the forward end of said housing when said barrel assembly is in its breech closed position, and port means located in the enlarged portion of said barrel member providing communication between said grooves and the atmosphere, said port means opening to the atmosphere at a point forward of the forward end of said housing when said barrel assembly is in its breech closed position.
 4. The powder-actuated tool of claim 3 further including a shroud member covering said enlarged end of said barrel member, said shroud having a forward inturned flange, said muzzle bushing having stop means thereon for limiting forward movement of said shroud relative to said barrel assembly spaced from the forward end of said barrel member, said flange extending into the space between said stop means and the forward end of said barrel member, the outer surface of said enlarged portion of said barrel member having reduced planar portions intersecting said port means.
 5. The powder-actuated tool of claim 3, said main barrel body having a further slot therein extending from a rearward point forward of said propellant charge receiving chamber to a forward point spaced rearwardly of the forward end of said housing when said barrel assembly is in its breech closed position, said tubular sleeve having a slot therein coextensive with said further slot, a pawl member mounted on said housing and having a portion extending through said slot in said sleeve and said further slot into the bore in said barrel assembly, a groove in the interior wall of said main barrel body extending from the forward end of said further slot to a forward point spaced axially forward of the forward end of said housing when said barrel assembly is in its breech closed position, and port means in said main barrel body providing communication between the forward end of the groove extending from said further slot and the atmosphere when the barrel assembly is in its breech closed position. 